Hydraulically damped body mount with bolt-through construction

ABSTRACT

A mount has an inner metal and an outer metal with an elastomeric bushing disposed between them. The elastomeric bushing includes a first pair of interconnected passages to control the damping rate during axial motion and a second, separate pair of interconnected passages to control the damping rate during motion orthogonal to the axial direction.

FIELD OF THE INVENTION

The present invention relates to a hydraulically damped mount. Moreparticularly, the present invention relates to a hydraulically dampedmount having a bolt through construction which has axial damping at onefrequency and radial damping at another frequency.

BACKGROUND OF THE INVENTION

There are numerous applications that exist where two members areattached to each other through a vibration damping device. Theseapplications include automobile body mounts, subframe mounts, cradlemounts, engine mounts and the like. The vibration damping devices dampenor isolate vibrations (including noises induced by the vibrations)between the two members.

A fluid filled active vibration damping device has been proposed as onetype of such vibration damping devices. The fluid filled device includesa first mounting member adapted to be attached to one of the twomembers; a second mounting member adapted to be attached to the other ofthe two members; an elastic body connecting the first and the secondmounting members; a pressure-receiving chamber partially defined by theelastic body and filled with a non-compressible fluid; an equilibriumchamber partially defined by a flexible layer and filled with thenon-compressible fluid; and an orifice passage permitting fluidcommunication between the pressure-receiving chamber and the equilibriumchamber. This fluid filled damping device is capable of exhibiting adesired vibration-damping effect on the basis of flows of the fluidthrough the orifice passage.

Generally, a fluid filled vibration-damping device is capable of dampingvibrations in one direction which is generally in an axial directionwith respect to the device. While this may be acceptable for avibration-damping device when it is used as an engine mount, when thesevibration-damping devices are used elsewhere in the vehicle, additionaldamping characteristics are needed for tuning the “noise, vibration andharshness” of the vehicle, especially when mounting a cab or a body on aframe.

SUMMARY OF THE INVENTION

The present invention provides the art with a hydraulically damped mountwhich makes it possible to have high damping at one particular frequencyin the axial direction and also to have high damping at a differentfrequency in one direction orthogonal to the axial direction.

The vibration-damping device of the present invention utilizes two setsof chambers which act independently in pairs to provide the desireddamping characteristics in directions that are generally perpendicularto each other.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a side view of the hydraulically damped mount in accordancewith the present invention;

FIG. 2 is an end view of the mount illustrated in FIG. 1;

FIG. 3 is a cross-sectional view of the mount illustrated in FIGS. 1 and2 taken in the direction of arrows 3-3 in FIG. 2;

FIG. 4 is a cross-sectional view of the mount illustrated in FIGS. 1 and2 taken in the direction of arrows 4-4 in FIG. 2;

FIG. 5 is a cutaway perspective view illustrating the passagesinterconnecting the various chambers;

FIG. 6 is a cross-sectional view similar to FIG. 3 but illustrating amount in accordance with another embodiment of the present invention inits as molded condition;

FIG. 7 is a cross-sectional view of the mount illustrated in FIG. 6 butshowing the mount in its operating position;

FIG. 8 is a cross-sectional view of a bushing in accordance with anotherembodiment of the present invention;

FIG. 9 is a cross-sectional view of the bushing illustrated in FIG. 8but showing the mount in its operating position;

FIG. 10 is a cross-sectional view of a hydraulically damped mount inaccordance with another embodiment of the present invention; and

FIG. 11 is a cross-sectional view of a hydraulically damped mount inaccordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

There is illustrated in FIGS. 1-5 a hydraulically damped mount inaccordance with the present invention and which is designated generallyby the reference numeral 10. Mount 10 comprises an outer metal 12, aninner metal 14 and a bushing assembly 16.

Outer metal 12 is a cup-shaped component which is adapted to be securedto one of the two members (not shown) attached together by mount 10.Outer metal 12 defines an open end 18 and a closed end 20. Closed end 20defines a circular aperture 22.

Inner metal 14 is a cylindrical component that includes a circularcylindrical portion 24 extending through aperture 22 of outer metal 12and a frusto-conical cylindrical portion 26 which extends out of openend 18 of outer metal 12. A flange 28 extends radially outwardly fromthe end of portion 26 to form a mounting surface 30 which is designed toengage the other of the two members being attached by mount 10.

Bushing assembly 16 is located between outer metal 12 and inner metal14. Bushing assembly 16 comprises an elastomeric bushing 32, an internaltube 34, a support disc 36 and a support ring 38. Inner metal 14,elastomeric bushing 32, internal tube 34, support disc 36 and supportring 38 are molded into a single component with inner metal 14, internaltube 34, support disc 36 and support ring 38 being bonded to elastomericbushing 32. Once molded, bushing assembly 16 is inserted into outermetal 12 and open end 18 of outer metal 12 is crimped or formed oversupport ring 38 to retain bushing assembly 16 within outer metal 12.Support disc 36 provides support for the interface between outer metal12 and elastomeric bushing 32.

An angular wall 50 of elastomeric bushing 32 and outer metal 12 define afirst or lower annular chamber 52. In addition, elastomeric bushing 32and outer metal 12 also define a second or upper annular chamber 54 anda fluid passageway 56 extending between chambers 52 and 54. Fluidpassageway 56 extends through one leg of internal tube 34 as shown inFIG. 5. Lower annular chamber 52, upper annular chamber 54 and fluidpassageway 56 are all filled with a non-compressible fluid which in thepreferred embodiment is a mixture of glycol and water. Internal tube 34provides support for upper annular chamber 54 and fluid passageway 56during the damping movement of mount 10.

During axial movement of inner metal 14 with respect to outer metal 12or an axial movement of outer metal 12 with respect to inner metal 14,(up and down in FIGS. 3 and 4.) angular wall 50 of elastomeric bushing32 deflects such that the volume of lower annular chamber 52 increasesor decreases. The change in volume of lower annular chamber 52 causesthe non-compressible fluid to flow through fluid passageway 56 betweenlower annular chamber 52 and upper annular chamber 54. The direction ofthe non-compressible fluid flow will be determined by whether lowerannular chamber 52 is increasing or decreasing in volume. In order toaccommodate an increase or decrease in the volume of upper annularchamber 54 when lower annular chamber 52 decreases or increases,respectively, in volume, an upper annular wall 58 of elastomeric bushing32 forms a diaphragm which will deflect or bulge out or in. The supportand attachment of support ring 38 maintains the integrity of upperannular chamber 54. The design of fluid passageway 56, lower annularchamber 52 and upper annular chamber 54 will determine the dampingcharacteristics for axial movement of mount 10.

Elastomeric bushing 32 and outer metal 12 define a third fluid chamber60, a fourth fluid chamber 62 located diametrically opposite to thirdfluid chamber 60 and a fluid passageway 64 extending between third andfourth fluid chambers 60 and 62. Fluid passageway 64 extends through oneleg of internal tube 34 as illustrated in FIG. 4. Third fluid chamber60, fourth fluid chamber 62 and fluid passageway 64 are filled with anon-compressible fluid which in the preferred embodiment is a mixture ofglycol and water. Internal tube 34 provides support for third fluidchamber 60, fourth fluid chamber 62 and fluid passageway 64, during thedamping movement of mount 10.

During a translational movement of inner metal 14 with respect to outermetal 12 or translational movement of outer metal 12 with respect toinner metal 14, (right and left directions in FIG. 4), elastomericbushing 32 will deflect to decrease the volume of either third fluidchamber 60 or fourth fluid chamber 62 depending on the direction of themovement. The decrease in volume of third fluid chamber 60 will causethe non-compressible fluid to flow from third fluid chamber 60 to fourthfluid chamber 62 through fluid passageway 64. In a similar manner, thedecrease in volume of fourth fluid chamber 62 will cause thenon-compressible fluid to flow from fourth fluid chamber 62 to thirdfluid chamber 60 through fluid passageway 64. The design for fluidpassageway 64 and third and fourth fluid chambers 60 and 62 willdetermine the damping characteristics for translational movement(orthogonal to the axial movement) for mount 10. Third fluid chamber 60and fourth fluid chamber 62 are located diametrically opposite to eachother. Thus, the damping characteristics for mount 10 in a directionorthogonal to the axial direction will be at a maximum in the right andleft directions illustrated in FIG. 4 and they will be at a minimum inthe right and left directions illustrated in FIG. 3. Mount 10 alsoincludes a rebound bumper or stop 66 as is well known in the art. A bolt68 secures the two members being attached and mount 10 as an assembly.

Referring now to FIGS. 6 and 7, a hydraulically damped mount 110 inaccordance with another embodiment of the present invention isillustrated. Mount 110 is the same as mount 10 except that an integrateddirt or heat shield 170 has been integrally molded with elastomericbushing 32. Shield 170 comprises a generally horizontal or disc shapedportion 172 and an upwardly angled frusto-conical section 174 asillustrated in FIG. 6. Once molded, as illustrated in FIG. 6, shield 170can be reversed to its working position illustrated in FIG. 7.Elastomeric shield 170 will flip through the middle position and intoits working or mirror position as illustrated in FIG. 7 due to what isknown as tin-lidding. Once reversed into its working position, shield170 protects mount 110 from both heat and dirt contamination.

Referring now to FIGS. 8 and 9, an elastomeric mount 210 in accordancewith another embodiment of the present invention is illustrated. Mount210 comprises a tubular outer metal 212, a tubular inner metal 214 andan annular bushing assembly 216. Bushing assembly 216 is a cylindricalcomponent comprising an elastomeric bushing 232 having a plurality ofvoids 234 and an outer housing 236.

Inner metal 214, elastomeric bushing 232 and outer housing 236 aremolded with elastomeric bushing 232 being bonded to both inner metal 214and outer housing 236. This assembly is then press-fit within outermetal 212 to complete the assembly of elastomeric mount 210. Mount 210dampens the movement between outer metal 212 and inner metal 214 due tothe deflection of elastomeric bushing 232. The design for elastomericbushing 232 including the design of voids 234 will determine the dampingcharacteristic for mount 210.

Similar to mount 110, mount 210 includes an integrated dirt or heatshield 270 integrally molded with elastomeric bushing 232. Shield 270includes an upwardly angled wall 274 as illustrated in FIG. 8. Oncemolded, as illustrated in FIG. 8, shield 270 can be reversed to itsworking position illustrated in FIG. 9. Elastomeric shield 270 will flipthrough the middle position and into its working or mirror position asillustrated in FIG. 9 due to what is known as tin-lidding. Once reversedinto its working position, shield 270 protects mount 210 from both heatand dirt contamination.

Referring now to FIG. 10, a hydraulically damped mount in accordancewith another embodiment of the present invention is illustrated and isdesignated generally by the reference numeral 310. Mount 310 comprises adie-cast case 312, an inner metal 314 and a bushing assembly 316.

Die-cast case 312 is an annular member which is adapted to be secured toone of the two members (not shown) attached together by mount 310.Die-cast case 312 defines an open end 318; a closed end 320 defining acircular aperture 322 and a channel 324.

Inner metal 314 is a cylindrical component that includes a circularcylindrical portion 326 extending through aperture 322 of die-cast case312. A flange 328 extends radially outwardly from the end of portion 326to form a mounting surface 330 which is designed to engage the other ofthe two members being attached by mount 310.

Bushing assembly 316 is located between die-cast case 312 and innermetal 314. Bushing assembly 316 comprises an elastomeric bushing 332, aninternal tube 334 and a die-cast tube 336. Inner metal 314, elastomericbushing 332, internal tube 334 and die-cast tube 336 are molded into asingle component with inner metal 314, internal tube 334 and die-casttube 336 being bonded to elastomeric bushing 332. Once molded, bushingassembly 316 is inserted into die-cast case 312 and internal tube 334 ispress fit within open end 318 of die-cast case 312 and die-cast tube 336is press fit within aperture 322 of die-cast case 312. While beingdescribed as being press-fit within aperture 322 of die-cast case 312,other method of attaching these two components is possible including butnot limited to the method described below for FIG. 11.

Once assembled to die-cast case 312, elastomeric bushing 332 sealinglyengages die-cast 312 at an inner surface 340 due to an O-ring style seal342 being formed into elastomeric bushing 332 and at an outer surface344 due to a rubber band type seal 346 also formed into elastomericbushing 332.

An angular wall 350 of elastomeric bushing 332 and die-cast case 312define a first or lower chamber 352. In addition, elastomeric bushing332 and die-cast case 312 form a second or upper chamber 354. Channel324 and a fluid passageway 356 in die-cast case 312 connects chambers352 and 354. Fluid passageway 356 extends through internal tube 334.Lower annular chamber 352, upper annular chamber 354, channel 324 andfluid passageway 356 are all filled with a non-compressible fluid whichin the preferred embodiment is a mixture of glycol and water.

During axial movement of inner metal 314 with respect to die-cast case312, (up and down in FIG. 10), angular wall 350 of elastomeric bushing332 deflects such that the volume of lower annular chambers 352increases or decreases. The change in volume in lower annular chamber352 causes the non-compressible fluid to flow through fluid passageway356, through channel 324, between lower annular chamber 352 and upperannular chamber 354. The direction of fluid flow will be determined bywhether lower annular chamber 352 is increasing or decreasing in volume.In order to accommodate an increase or decrease in volume of upperannular chamber 354, an upper annular wall 358 of elastomeric bushing332 forms a diaphragm which will deflect or bulge in or out. The designof channel 324, fluid passageway 356 and chambers 352 and 354 willdetermine the damping characteristics for axial movement of mount 310.

Referring now to FIG. 11, a hydraulically damped mount in accordancewith another embodiment of the present invention is illustrated and isdesignated generally by the reference numeral 410. Mount 410 comprises adie-cast case 412, an inner metal 414 and a bushing assembly 416.

Die-cast case 412 is an annular member which is adapted to be secured toone of the two members (only one shown) attached together by mount 410.Die-cast case 412 defines an open end 418; a closed end 420 defining acircular aperture 422 and a channel 424.

Inner metal 414 is a cylindrical component that includes a circularcylindrical portion 426 extending through aperture 422 of die-cast case412. A flange 428 extends radially outwardly from the end of portion 426to form a mounting surface 430 which is designed to engage the other ofthe two members being attached by mount 410.

Bushing assembly 416 is located between die-cast case 412 and innermetal 414. Bushing assembly 416 comprises an elastomeric bushing 432, aninternal tube 434 and a die-cast tube 436. Inner metal 414, elastomericbushing 432, internal tube 434 and die-cast tube 436 are molded into asingle component with inner metal 414, internal tube 434 and die-casttube 436 being bonded to elastomeric bushing 432. Once molded, bushingassembly 416 is inserted into die-cast case 412 and internal tube 434 ispress fit within open end 418 of die-cast case 412 and die-cast tube 436extends through aperture 322 of die-cast case 312 and is attached todie-cast case 312 by being pop-riveted or by other methods know well inthe art.

Once assembled to die-cast case 412, elastomeric bushing 432 sealinglyengages die-cast case 412 at an inner surface 440 due to an O-ring styleseal 442 being formed into elastomeric bushing 432 and at an outersurface 444 due to a rubber band type seal 446 also formed intoelastomeric bushing 432.

An angular wall 450 of elastomeric bushing 432 and die-cast case 412define a first or lower chamber 452. In addition, elastomeric bushing432 and die-cast case 412 form a second or upper chamber 454. Channel424 and a fluid passageway 456 in die-cast case 412 connects chambers452 and 454. Fluid passageway 456 extends through internal tube 434.Lower annular chamber 452, upper annular chamber 454, channel 424 andfluid passageway 456 are all filled with a non-compressible fluid whichin the preferred embodiment is a mixture of glycol and water.

During axial movement of inner metal 414 with respect to die-cast case412, (up and down in FIG. 11), angular wall 450 of elastomeric bushing432 deflects such that the volume of lower annular chambers 452increases or decreases. The change in volume in lower annular chamber452 causes the non-compressible fluid to flow through fluid passageway456, through channel 424, between lower annular chamber 452 and upperannular chamber 454. The direction of fluid flow will be determined bywhether lower annular chamber 452 is increasing or decreasing in volume.In order to accommodate an increase or decrease in volume of upperannular chamber 454, an upper annular wall 458 of elastomeric bushing432 forms a diaphragm which will deflect or bulge in or out. The designof channel 424, fluid passageway 456 and chambers 452 and 454 willdetermine the damping characteristics for axial movement of mount 410.

A rebound mount 460 is also attached to mount 410. Rebound mount 460comprises an outer metal 462, an end cap 464 and a bushing assembly 466.Outer metal 462 is a cup-shaped component which defines an open end 468and a closed end 470. Closed end 470 defines an outer flange 472 whichis received within the internal diameter of die-cast tube 436 of bushingassembly 416.

End cap 464 is an annular member which defines a central aperture 474.Bolt 68 (not shown) extends through the two members being attached,inner metal 414 and end cap 464 to secure the mounting system.

Bushing assembly 466 is located between outer metal 462 and inner metal414. Bushing assembly 466 comprises an elastomeric bushing 482 and aninternal tube 484. Elastomeric bushing 482 and internal tube 484 aremolded into a single component with internal tube 484 being bonded toelastomeric bushing 482. Once molded, bushing assembly 466 is insertedinto outer metal 462 and the outer end of internal tube 484 is crimpedor formed over open end 468 of outer metal 462 to retain bushingassembly 466 within outer metal 462. This assembly is then attached tomount 410 by assembling elastomeric bushing 482 over inner metal 414 andby engaging outer flange 472 with die-cast tube 436. Elastomeric bushing482 can form an interference fit with inner metal 414 or elastomericbushing 482 can be bonded to inner metal 414. When assembled to thevehicle, bolt 68 (not shown) extends through the two components beingjoined, inner metal 414 and end cap 464 to secure the mounting system.The gap between end cap 464 and inner metal 414 in conjunction withelastomeric bushing 482 acts as a rebound stop for the mounting system.

Elastomeric bushing 482 and outer metal 462 define a third fluid chamber490, a fourth fluid chamber 492 located diametrically opposite to thirdfluid chamber 490 and a fluid passageway 494 extending between third andfourth fluid chambers 490 and 492. Fluid passageway 494 extends throughone leg of internal tube 484. Third fluid chamber 490, fourth fluidchamber 492 and fluid passageway 494 are filled with a non-compressiblefluid which in the preferred embodiment is a mixture of glycol andwater. Internal tube 484 provides support for third fluid chamber 490,fourth fluid chamber 492 and fluid passageway 494, during the dampingmovement of rebound mount 460.

During a translational movement of inner metal 414 with respect to outermetal 462 or translational movement of outer metal 462 with respect toinner metal 414, (right and left directions in FIG. 11), elastomericbushing 482 will deflect to decrease the volume of either third fluidchamber 490 or fourth fluid chamber 492 depending on the direction ofthe movement. The decrease in volume of third fluid chamber 490 willcause the non-compressible fluid to flow from third fluid chamber 490 tofourth fluid chamber 492 through fluid passageway 494. In a similarmanner, the decrease in volume of fourth fluid chamber 492 will causethe non-compressible fluid to flow from fourth fluid chamber 492 tothird fluid chamber 490 through fluid passageway 494. The design forfluid passageway 494 and third and fourth fluid chambers 490 and 492will determine the damping characteristics for translational movement(orthogonal to the axial movement) for rebound mount 460. Third fluidchamber 490 and fourth fluid chamber 492 are located diametricallyopposite to each other. Thus, the damping characteristics for reboundmount 460 in a direction orthogonal to the axial direction will be at amaximum in the right and left directions illustrated in FIG. 11 and theywill be at a minimum in directions perpendicular to those shown in FIG.11.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A mount comprising: an inner metal; an outer metal disposed aroundsaid inner metal to form a gap between said inner and outer metals; anelastomeric bushing disposed within said gap between said inner andouter metals, said elastomeric bushing including a wall covering saidgap; and a first chamber defined between said elastomeric bushing andsaid outer metal.
 2. The mount according to claim 1, further comprisinga second chamber defined between said elastomeric bushing and said outermetal.
 3. The mount according to claim 2, further comprising apassageway in communication with said first and second chambers.
 4. Themount according to claim 3, wherein said passageway is defined by saidelastomeric bushing and said outer metal.
 5. The mount according toclaim 2, further comprising a third chamber defined between saidelastomeric bushing and said outer metal.
 6. The mount according toclaim 5, further comprising a fourth chamber defined between saidelastomeric bushing and said outer metal.
 7. The mounting according toclaim 6, further comprising a first passageway in communication withsaid first and second chambers and a second passageway in communicationwith said third and fourth chambers.
 8. The mounting according to claim7, wherein the chambers and passageways are filled with a fluid, a firstdamping characteristic being defined in a first direction by said firstchamber, said first passageway and said second chamber, and a seconddamping characteristic being defined in a second direction by said thirdchamber, said second passageway and said second chamber.
 9. The mountingaccording to claim 8, wherein said second direction is orthogonal tosaid first direction.
 10. The mounting according to claim 6, whereinsaid first passageway is defined by said elastomeric bushing and saidouter metal.
 11. The mounting according to claim 10, wherein said secondpassageway is defined by said elastomeric bushing and said outer metal.12. The mounting according to claim 6, further comprising an internaltube disposed between said inner metal and said outer metal.
 13. Themounting according to claim 1, further comprising an internal tubedisposed between said inner metal and said outer metal.
 14. A mountcomprising: an inner metal; an outer metal disposed around said innermetal; and an elastomeric bushing disposed between said inner and outermetals; wherein: said elastomeric bushing defines a first fluid chamber,a second fluid chamber and a first fluid passageway connecting saidfirst and second fluid chambers, movement of one of said inner and outermetals with respect to the other of said inner and outer metals in afirst direction being controlled by said first fluid chamber, saidsecond fluid chamber and said first fluid passageway; said elastomericbushing defines a third fluid chamber, a fourth fluid chamber and asecond fluid passageway connecting said third and fourth fluid chambers,movement of one of said inner and outer metals with respect to the otherof said inner and outer metals in a second direction being controlled bysaid third fluid chamber, said fourth fluid chamber and said secondfluid passageway; said second direction being orthogonal to said firstdirection.
 15. The mounting according to claim 14, wherein the chambersand the passageways are filled with a fluid, a first dampingcharacteristic being defined in said first direction by said firstchamber, said first fluid passageway and said second chamber, and asecond damping characteristic being defined in the second direction bysaid third chamber, said second fluid passageway and said fourthchamber.
 16. The mounting according to claim 14, wherein said firstpassageway is defined by said elastomeric bushing and said outer metal.17. The mounting according to claim 16, wherein said second passagewayis defined by said elastomeric bushing and said outer metal.
 18. Themounting according to claim 14, further comprising an internal tubedisposed between said inner metal and said outer metal.